The present invention relates to a write once-type recording medium and a recording apparatus thereof.
In recent years, as for a recording medium, a write once-type optical disc has attracted users' attention and a lot of writable materials have been developed. The write once-type optical disc usually has a pre-groove (guide groove) for guiding the light beam used for writing or reading.
The CD-WO (compact disc for write once use) proposed by PHILIPS CO. has the pre-groove which is wobbled by a wobbling signal for obtaining the precise tracking control signal of the light beam. As the result of wobbling, the pre-groove is displaced on both sides of the regular position of the track in accordance with the wobbling signal.
According to the proposed standard, the CD-WO is provided with the pre-groove which is recorded with time-codes in the format as shown in FIG. 1.
Each time-code comprises codes designating a synchronizing signal(SYNC), minute, second, frame number and an error-correcting code, successively and are superimposed on the wobbling signal.
In the CD-WO, its recording area is divided in many tiny segments called a frame and 75 frames correspond to the period of 1 second. For indicating or managing the absolute position of these frames, each frame has a peculiar time code, For example, the time code of the first frame on a disc is "00 00 00" (=00 minute, 00 second and 00th frame) and that of the next frame is "00 00 01" and so on.
The time-codes so recorded are obtained by demodulating the tracking control signal which is obtained from a reflected light of such as a data writing-light, data reading-light and tracking light. The time-codes obtained as above are then used for data-writing/reading.
FIG. 2 shows an example of correspondence between the position on a write once-type optical disc and time-codes. On the position "12' 14" 73F ", for example, the time - code "12 minutes, 14 seconds and 73rd frame" is recorded.
As described before, there are many materials for write once use and therefore it is desirable that the writing characteristics of the disc are recorded previously for setting writing parameters.
A write once-type optical disc capable of storing large amount of data is classified into such disc types as a partial write once-type and full write once-type.
The former has a read only field formed on the inner peripheral portion of the disc, the field recorded with data with protection prior to use and a write-once field formed on the outer peripheral portion of the disc.
The latter has a read only field prerecorded with data and formed on the inner peripheral portion of the disc and a write once field formed on the peripheral portion thereof.
The write once-type disc described as above requires writing-management data for indicating a border between the read only field and write once field, and the writing characteristics.
The writing-management data are not always necessary in the case of data-writing but the time-codes are. The data of the border is necessary only on the first write once, after that file and directory management, etc., follow.
On the other hand, the data such as the writing output is necessary only on the beginning of every write once. After that, the output is maintained.
Consequently, with respect to the writing-management data, the data must be fed to a recording apparatus on every writing and the write once-type optical disc is limited to the one which meets the data set in a recording apparatus.
This results in the write once-type optical disc being used in limited purposes. Furthermore, if the writing-management data are prerecorded in the data-recording field of the write once-type optical disc, the disc will be incompatible with widely known read only optical discs.